Bloodraven

Not Maekar after all, Dunk knew, when he saw those banners. The banners of the Prince of Summerhall showed four three-headed dragons, two and two, the arms of the fourth-born son of the late King Daeron II Targaryen. A single white dragon announced the presence of the King’s Hand, Lord Brynden Rivers.

Bloodraven himself had come to Whitewalls.